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#include <time.h>
#include <cassert>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <opkele/data.h>
#include <opkele/basic_op.h>
#include <opkele/exception.h>
#include <opkele/util.h>
#include <opkele/uris.h>
namespace opkele {
void basic_op::reset_vars() {
assoc.reset();
return_to.clear(); realm.clear();
claimed_id.clear(); identity.clear();
invalidate_handle.clear();
}
bool basic_op::has_return_to() const {
return !return_to.empty();
}
const string& basic_op::get_return_to() const {
if(return_to.empty())
throw no_return_to(OPKELE_CP_ "No return_to URL provided with request");
return return_to;
}
const string& basic_op::get_realm() const {
assert(!realm.empty());
return realm;
}
bool basic_op::has_identity() const {
return !identity.empty();
}
const string& basic_op::get_claimed_id() const {
if(claimed_id.empty())
throw non_identity(OPKELE_CP_ "attempting to retrieve claimed_id of non-identity related request");
assert(!identity.empty());
return claimed_id;
}
const string& basic_op::get_identity() const {
if(identity.empty())
throw non_identity(OPKELE_CP_ "attempting to retrieve identity of non-identity related request");
assert(!claimed_id.empty());
return identity;
}
bool basic_op::is_id_select() const {
return identity==IDURI_SELECT20;
}
void basic_op::select_identity(const string& c,const string& i) {
claimed_id = c; identity = i;
}
void basic_op::set_claimed_id(const string& c) {
claimed_id = c;
}
basic_openid_message& basic_op::associate(
basic_openid_message& oum,
const basic_openid_message& inm) try {
assert(inm.get_field("mode")=="associate");
util::dh_t dh;
util::bignum_t c_pub;
unsigned char key_digest[SHA256_DIGEST_LENGTH];
size_t d_len = 0;
enum {
sess_cleartext, sess_dh_sha1, sess_dh_sha256
} st = sess_cleartext;
string sts = inm.get_field("session_type");
string ats = inm.get_field("assoc_type");
if(sts=="DH-SHA1" || sts=="DH-SHA256") {
if(!(dh = DH_new()))
throw exception_openssl(OPKELE_CP_ "failed to DH_new()");
c_pub = util::base64_to_bignum(inm.get_field("dh_consumer_public"));
try { dh->p = util::base64_to_bignum(inm.get_field("dh_modulus"));
}catch(failed_lookup&) {
dh->p = util::dec_to_bignum(data::_default_p); }
try { dh->g = util::base64_to_bignum(inm.get_field("dh_gen"));
}catch(failed_lookup&) {
dh->g = util::dec_to_bignum(data::_default_g); }
if(!DH_generate_key(dh))
throw exception_openssl(OPKELE_CP_ "failed to DH_generate_key()");
vector<unsigned char> ck(DH_size(dh)+1);
unsigned char *ckptr = &(ck.front())+1;
int cklen = DH_compute_key(ckptr,c_pub,dh);
if(cklen<0)
throw exception_openssl(OPKELE_CP_ "failed to DH_compute_key()");
if(cklen && (*ckptr)&0x80) {
(*(--ckptr)) = 0; ++cklen; }
if(sts=="DH-SHA1") {
SHA1(ckptr,cklen,key_digest); d_len = SHA_DIGEST_LENGTH;
}else if(sts=="DH-SHA256") {
SHA256(ckptr,cklen,key_digest); d_len = SHA256_DIGEST_LENGTH;
}else
throw internal_error(OPKELE_CP_ "I thought I knew the session type");
}else
throw unsupported(OPKELE_CP_ "Unsupported session_type");
assoc_t assoc;
if(ats=="HMAC-SHA1")
assoc = alloc_assoc(ats,SHA_DIGEST_LENGTH,true);
else if(ats=="HMAC-SHA256")
assoc = alloc_assoc(ats,SHA256_DIGEST_LENGTH,true);
else
throw unsupported(OPKELE_CP_ "Unsupported assoc_type");
oum.reset_fields();
oum.set_field("ns",OIURI_OPENID20);
oum.set_field("assoc_type",assoc->assoc_type());
oum.set_field("assoc_handle",assoc->handle());
oum.set_field("expires_in",util::long_to_string(assoc->expires_in()));
secret_t secret = assoc->secret();
if(sts=="DH-SHA1" || sts=="DH-SHA256") {
if(d_len != secret.size())
throw bad_input(OPKELE_CP_ "Association secret and session MAC are not of the same size");
oum.set_field("session_type",sts);
oum.set_field("dh_server_public",util::bignum_to_base64(dh->pub_key));
string b64; secret.enxor_to_base64(key_digest,b64);
oum.set_field("enc_mac_key",b64);
}else /* TODO: support cleartext over encrypted connection */
throw unsupported(OPKELE_CP_ "Unsupported session type");
return oum;
} catch(unsupported& u) {
oum.reset_fields();
oum.set_field("ns",OIURI_OPENID20);
oum.set_field("error",u.what());
oum.set_field("error_code","unsupported-type");
oum.set_field("session_type","DH-SHA256");
oum.set_field("assoc_type","HMAC-SHA256");
return oum;
}
void basic_op::checkid_(const basic_openid_message& inm,
extension_t *ext) {
reset_vars();
string mode = inm.get_field("mode");
if(mode=="checkid_setup")
mode = mode_checkid_setup;
else if(mode=="checkid_immediate")
mode = mode_checkid_immediate;
else
throw bad_input(OPKELE_CP_ "Invalid checkid_* mode");
try {
assoc = retrieve_assoc(invalidate_handle=inm.get_field("assoc_handle"));
invalidate_handle.clear();
}catch(failed_lookup&) {
// no handle specified or no valid assoc found, go dumb
assoc = alloc_assoc("HMAC-SHA256",SHA256_DIGEST_LENGTH,true);
}
try {
openid2 = (inm.get_field("ns")==OIURI_OPENID20);
}catch(failed_lookup&) { openid2 = false; }
try {
return_to = inm.get_field("return_to");
}catch(failed_lookup&) { }
if(openid2) {
try {
realm = inm.get_field("realm");
}catch(failed_lookup&) {
try {
realm = inm.get_field("trust_root");
}catch(failed_lookup&) {
if(return_to.empty())
throw bad_input(OPKELE_CP_
"Both realm and return_to are unset");
realm = return_to;
}
}
}else{
try {
realm = inm.get_field("trust_root");
}catch(failed_lookup&) {
if(return_to.empty())
throw bad_input(OPKELE_CP_
"Both realm and return_to are unset");
realm = return_to;
}
}
try {
identity = inm.get_field("identity");
try {
claimed_id = inm.get_field("claimed_id");
}catch(failed_lookup&) {
if(openid2)
throw bad_input(OPKELE_CP_
"claimed_id and identity must be either both present or both absent");
}
}catch(failed_lookup&) {
if(openid2 && inm.has_field("claimed_id"))
throw bad_input(OPKELE_CP_
"claimed_id and identity must be either both present or both absent");
}
verify_return_to();
}
basic_openid_message& basic_op::id_res(basic_openid_message& om) {
assert(assoc);
assert(!return_to.empty());
assert(!is_id_select());
time_t now = time(0);
struct tm gmt; gmtime_r(&now,&gmt);
char w3timestr[24];
if(!strftime(w3timestr,sizeof(w3timestr),"%Y-%m-%dT%H:%M:%SZ",&gmt))
throw failed_conversion(OPKELE_CP_
"Failed to build time string for nonce" );
om.set_field("ns",OIURI_OPENID20);
om.set_field("mode","id_res");
om.set_field("op_endpoint",get_op_endpoint());
string ats = "ns,mode,op_endpoint,return_to,response_nonce,"
"assoc_handle,signed";
if(!identity.empty()) {
om.set_field("identity",identity);
om.set_field("claimed_id",claimed_id);
ats += ",identity,claimed_id";
}
om.set_field("return_to",return_to);
string nonce = w3timestr;
om.set_field("response_nonce",alloc_nonce(nonce,assoc->stateless()));
if(!invalidate_handle.empty()) {
om.set_field("invalidate_handle",invalidate_handle);
ats += ",invalidate_handle";
}
om.set_field("assoc_handle",assoc->handle());
om.add_to_signed(ats);
om.set_field("sig",util::base64_signature(assoc,om));
return om;
}
basic_openid_message& basic_op::cancel(basic_openid_message& om) {
assert(!return_to.empty());
om.set_field("ns",OIURI_OPENID20);
om.set_field("mode","cancel");
return om;
}
basic_openid_message& basic_op::error(basic_openid_message& om,
const string& error,const string& contact,
const string& reference ) {
assert(!return_to.empty());
om.set_field("ns",OIURI_OPENID20);
om.set_field("mode","error");
om.set_field("error",error);
om.set_field("contact",contact);
om.set_field("reference",reference);
return om;
}
basic_openid_message& basic_op::setup_needed(
basic_openid_message& oum,const basic_openid_message& inm) {
assert(mode==mode_checkid_immediate);
assert(!return_to.empty());
if(openid2) {
oum.set_field("ns",OIURI_OPENID20);
oum.set_field("mode","setup_needed");
}else{
oum.set_field("mode","id_res");
static const string setupmode = "checkid_setup";
oum.set_field("user_setup_url",
util::change_mode_message_proxy(inm,setupmode)
.append_query(get_op_endpoint()));
}
return oum;
}
basic_openid_message& basic_op::check_authentication(
basic_openid_message& oum,
const basic_openid_message& inm) try {
assert(inm.get_field("mode")=="check_authentication");
oum.reset_fields();
oum.set_field("ns",OIURI_OPENID20);
bool o2;
try {
o2 = (inm.get_field("ns")==OIURI_OPENID20);
}catch(failed_lookup&) { o2 = false; }
string nonce;
if(o2) {
try {
if(!check_nonce(nonce = inm.get_field("response_nonce")))
throw failed_check_authentication(OPKELE_CP_ "Invalid nonce");
}catch(failed_lookup&) {
throw failed_check_authentication(OPKELE_CP_ "No nonce provided with check_authentication request");
}
}
try {
assoc = retrieve_assoc(inm.get_field("assoc_handle"));
if(!assoc->stateless())
throw failed_check_authentication(OPKELE_CP_ "Will not do check_authentication on a stateful handle");
}catch(failed_lookup&) {
throw failed_check_authentication(OPKELE_CP_ "No assoc_handle or invalid assoc_handle specified with check_authentication request");
}
static const string idresmode = "id_res";
try {
if(util::base64_signature(assoc,util::change_mode_message_proxy(inm,idresmode))!=inm.get_field("sig"))
throw failed_check_authentication(OPKELE_CP_ "Signature mismatch");
}catch(failed_lookup&) {
throw failed_check_authentication(OPKELE_CP_ "failed to calculate signature");
}
oum.set_field("is_valid","true");
try {
string h = inm.get_field("invalidate_handle");
try {
assoc_t ih = retrieve_assoc(h);
}catch(invalid_handle& ih) {
oum.set_field("invalidate_handle",h);
}catch(failed_lookup& ih) {
oum.set_field("invalidate_handle",h);
}
}catch(failed_lookup&) { }
if(o2) {
assert(!nonce.empty());
invalidate_nonce(nonce);
}
return oum;
}catch(failed_check_authentication& ) {
oum.set_field("is_valid","false");
return oum;
}
void basic_op::verify_return_to() {
if(realm.find('#')!=string::npos)
throw opkele::bad_realm(OPKELE_CP_ "authentication realm contains URI fragment");
if(!util::uri_matches_realm(return_to,realm))
throw bad_return_to(OPKELE_CP_ "return_to URL doesn't match realm");
}
}
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